In conventional sets of “iron” golf clubs, each club includes a shaft with a club head attached to one end and a grip attached to the other end. The club head includes a face for striking a golf ball. The angle between the face and a vertical plane is called “loft.” In general, the greater the loft is of the golf club in a set, the greater the launch angle and the less distance the golf ball is hit.
A set of irons generally includes irons that are designated number 3 through number 9 and a pitching wedge. The iron set is generally complimented by a series of wedges, such as a pitching wedge, a lob wedge, a gap wedge, and/or a sand wedge. Sets can also include a 1 iron and a 2 iron, but these clubs are generally sold separate from the set. Each iron has a shaft length that usually decreases through the set as the loft for each club head increases, from the long irons to the short irons. The length of the club, along with the club head loft and center of gravity impart various performance characteristics to the ball's launch conditions upon impact. The initial trajectory of the ball generally extends between the impact point and the apex or peak of the trajectory. In general, the ball's trajectory for long irons, like the 3 iron, is a more penetrating, lower trajectory due to the lower launch angle and the increased ball speed off of the club. Short irons, like the 8 iron or pitching wedge, produce a trajectory that is substantially steeper and less penetrating than the trajectory of balls struck by long irons. The highest point of the long iron's ball flight is lower than the highest point for the short iron's ball flight. The mid irons, such as the 5 iron, produce an initial trajectory that is between those exhibited by balls hit with the long and short irons.
One of the major problems for players is that the lower launch angle of the golf balls hit with long irons leads to a low angle of descent. Because the ultimate peak height is less and the ball is traveling at a faster pace, the angle of descent can be very low. Thus, the ball can hit near a targeted area and then continue to roll for an extended distance. With short irons, players are generally able to hit the ball close to the intended target and the ball will remain close to the point of impact after it hits the ground. It would be desirable to have all the club heads in a set produce a relatively consistent peak height and, particularly, a more consistent angle of descent through the set. This would allow golfers to improve their performance and confidence.